So far, I've been pleased with the fidelity of UFO:AI to the old X-Com series.
However, as a long-time X-Com fan, I'm missing some of the same grenade implementations that other spin-offs, tributes & similar games have neglected - grenade specifics.
- Timers: For High-Explosives especially, but also Proximity mines it was handy to give your team a set amount of turns to evacuate an area.
- Armed, but held: There was a mechanic that was similar to priming a grenade but holding the trigger in the first two games. This let me give soldiers a "self-destruct" mode. That way, if an alien was nearby and took me out, the soldier would drop the grenade and it would detonate. The trade-off to using this strategy was occasional loss of equipment and the danger of doing this with Proximity mines if I were to go for an equipment retrieval. Of course, these presented the same dangers to nearby civilians. (It was also great for situations dealing with psionic possession or cryssalid (sp?) takeovers)
If these could be added, I'd have little reason to re-load the old DOS X-Com when I got the itch versus playing UFO:AI.